DOCSLIB.ORG

The Surprising Lunar Maria

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Surprising Lunar Maria PSRD Hot Idea: Titanium in lunar maria http://www.psrd.hawaii.edu/June00/lunarMaria.html posted June 23, 2000 The Surprising Lunar Maria Written by G. Jeffrey Taylor Hawai'i Institute of Geophysics and Planetology The lunar maria, the dark, smooth areas on the Moon, formed when lava flowed across the surface billions of years ago. Samples returned from the Moon by astronauts and by automated spacecraft suggested that the maria consist mostly of basalts with either low (less than about 5 wt%) or high (more than about 9 wt%) contents of titanium dioxide (TiO2). Scientists wondered why there were so few lava flows with intermediate titanium concentrations, and they invented some elaborate, interesting explanations. However, the samples came from only a few places on the Moon. Recently, Tom Giguere and his colleagues at the University of Hawai'i used data from the Galileo and Clementine missions to evaluate the compositions of the maria over the entire lunar globe. Their results show that there are plenty of lava flows with intermediate amounts of TiO2; in fact, there is a continuous spectrum of titanium contents from low (most abundant) to high (least abundant). This gives a different view of the nature of the lunar interior, and is consistent with the idea that the Moon melted soon after it formed. References: Giguere, T., Taylor, G. J., Hawke, B. R., and Lucey, P. G. (2000) The titanium contents of lunar mare basalts. Meteoritics and Planetary Science, vol. 35, p. 193-200. Moon Rocks The samples returned by the piloted American Apollo missions and the robotic Russian Luna missions have been a rich source of precise data about the Moon. Chemical analyses of rocks from the lunar maria revealed a startling range in the amount of TiO2 (titanium dioxide) present. (Chemists express analyses of rocks as oxides because most elements are chemically bound to oxygen in rocks.) However, with only a few exceptions, the rocks are either low in Ti (about 5 wt% TiO2 or less) or high in Ti (more than 9 wt% TiO2). Top: Piece of mare basalt collected by astronauts during the Apollo 15 mission. The holes are bubbles of escaping gas trapped when the rock solidified. Such features, called vesicles, are common in lava flows on the Earth. Bottom: Photograph taken with a microscope using polarized light of a thin slice (30 micrometers thick) of a mare basalt from the Apollo 15 mission. Yellow and orange mineral is pyroxene; grayish mineral is plagioclase feldspar. 1 of 5 PSRD Hot Idea: Titanium in lunar maria http://www.psrd.hawaii.edu/June00/lunarMaria.html Above: Analyses of rock samples returned from the Moon suggest that basalts from the lunar maria are either high or low in titanium. Few samples plot in the gap between the two prominent peaks on this frequency histogram. This two-peaked (or 'bimodal') distribution of TiO2 concentrations in lunar basalts had become embedded in our thinking about the Moon. Because magmas are created by partial melting deep inside a planet, most investigators reasoned that the two groups must have formed from two compositionally distinct rock types in the lunar mantle. One was low in titanium, the other high. Some smearing out of titanium occurred by mixing of magmas from the two sources, or even by mixing of the two sources by solid convection in the mantle. It was still surprising that so few lavas had intermediate titanium contents. It turns out that lots of lavas have intermediate titanium. A Global Assessment of Titanium Paul Lucey (U. Hawai'i) has modified an established technique to determine the TiO2 concentration of the lunar surface from the amount of light reflected at two different wavelengths. Working with Lucey and Brad Jolliff (Washington University in St. Louis) David Blewett (U. Hawai'i) used samples from known locations on the Moon to calibrate the technique [See PSRD article: Moonbeams and Elements]. In essence, the method measures the amount of dark mineral grains in the lunar surface, which is related to the amount of the mineral ilmenite (FeTiO3). If a dark mineral that does not contain titanium is present, the method can give erroneous results. Fortunately, ilmenite is common in all basalts returned from the Moon. Giguere and coworkers used this technique to determine the TiO2 contents of all the lunar maria. The map below shows the distribution of titanium on the Earth-facing side of the Moon, where almost all the lunar maria occur. (Because of gravitational forces, the Moon always keeps the same hemisphere facing Earth.) On the map, the colors represent different TiO2 concentrations. There are large orange areas of the maria, indicating an intermediate TiO2 concentration. In fact, those areas appear to be more abundant than are areas of high-TiO2. 2 of 5 PSRD Hot Idea: Titanium in lunar maria http://www.psrd.hawaii.edu/June00/lunarMaria.html Above: Map of TiO2 concentrations in the lunar maria on the nearside of the Moon, determined from images obtained by the Galileo spacecraft. Highland areas (black) have been masked out. When converted to a frequency diagram, the TiO2 data are strikingly different from the distribution shown by the returned samples. Low-Ti basalts are still the most abundant, but there is a continuous decrease in abundance from a peak between 2 and 3 wt%. High-Ti basalts are the least abundant. The remote sensing data for the lunar maria tend to be shifted to slightly lower TiO2 values because impacts cause mixing with nearby and underlying highland rocks, which contain only small amounts of TiO2, usually less than 1 wt%. Giguere and his colleagues show that on average a mare surface contains about 20% less TiO2 than do the basalt lava flows making up the maria. Thus, the surface of a maria developed on lava flows that contained 10 wt% TiO2 would contain only about 8 wt% TiO2. Nevertheless, the relative abundance of low-, intermediate-, and high-Ti basalts remains unchanged. Above: The TiO2 concentrations of the maria on the entire nearside of the Moon are distributed very differently than indicated by the returned rocks alone. The two-peaked distribution shown by rocks is probably due to restricted sampling by the six Apollo and three Luna missions--they did not land on flows with intermediate titanium concentrations. A Few Complications Do we really know the composition of the basalts making up the lunar maria? Analysis of samples and the remote sensing data give very different views of the nature of mare basalts. One possibility is that the intermediate-Ti maria were 3 of 5 PSRD Hot Idea: Titanium in lunar maria http://www.psrd.hawaii.edu/June00/lunarMaria.html created by impact mixing of low-Ti and high-Ti basalts that overlie one another or lie adjacent to one another. Certainly this is possible in some cases, such as areas in high-Ti maria near the borders with the highlands (which have very little titanium), but Giguere and his coworkers argue that it is unlikely that such mixing is so efficient that it can account for the low abundance of high-Ti basalts. Furthermore, there are sharp boundaries between low- and high-Ti maria or regions within maria, showing that the impacts do not mix thoroughly. Giguere and his colleagues conclude that the remote sensing data give an accurate picture of the relative abundance of basalts with different titanium concentrations. The Lunar Prospector mission also measured titanium on the lunar surface, using two totally different techniques based on neutron interactions in the lunar surface rather than the light reflected from it. Although the Prospector data have much less spatial resolution (pixels about 100 kilometers across versus about 1 kilometer for the data used by Giguere), there is general agreement. However, there are some significant differences in a few areas. Nobody has yet figured out the cause of these differences, but the total area affected is small and does not alter the basic shape of the frequency histogram. In fact, none of the problem areas have intermediate TiO2 contents. The Lunar Interior One of the goals in analyzing the compositions of basalt lava flows on a planet is to determine the nature of the planet's mantle. This is possible because partial melting of the interior produces magmas. Rocks melt over a range of temperatures, not all at once. The composition of the melted portion (which becomes magma) varies with the amount of melting and with the composition of the rock melting. Thus, it is in principle possible to use the compositions of basalts on the Moon to estimate the composition of the lunar interior. The large range in titanium contents of mare basalts suggests a wide range in the titanium contents inside the Moon. Giguere and his co-authors note that the distribution of TiO2 contents of mare basalts is consistent with formation of the lunar mantle rocks from a global magma ocean, coupled with sinking of dense rocks formed in it. A well-established tenet of lunar science is that the Moon was surrounded by a globe-encircling ocean of magma soon after it formed [See PSRD article: Moonbeams and Elements.] As this swirling, hot mass began to crystallize, minerals with high densities (olivine and pyroxene) sank and those with densities lower than the magma (especially feldspar) rose to form the initial crust. As crystallization continued, the magma became increasingly rich in TiO2 until ilmenite (FeTiO3) crystallized. The first minerals to sink would have accumulated into rocks with small concentrations of titanium. When these remelted hundreds of millions of years later, they would form low-Ti basalts. About 65% of the solidified magma ocean would have consisted of such low-Ti mantle rocks, accounting for the high abundance of low-Ti basalts.
Load more

Recommended publications
  • Lunar Impact Crater Identification and Age Estimation with Chang’E
    ARTICLE https://doi.org/10.1038/s41467-020-20215-y OPEN Lunar impact crater identification and age estimation with Chang’E data by deep and transfer learning ✉ Chen Yang 1,2 , Haishi Zhao 3, Lorenzo Bruzzone4, Jon Atli Benediktsson 5, Yanchun Liang3, Bin Liu 2, ✉ ✉ Xingguo Zeng 2, Renchu Guan 3 , Chunlai Li 2 & Ziyuan Ouyang1,2 1234567890():,; Impact craters, which can be considered the lunar equivalent of fossils, are the most dominant lunar surface features and record the history of the Solar System. We address the problem of automatic crater detection and age estimation. From initially small numbers of recognized craters and dated craters, i.e., 7895 and 1411, respectively, we progressively identify new craters and estimate their ages with Chang’E data and stratigraphic information by transfer learning using deep neural networks. This results in the identification of 109,956 new craters, which is more than a dozen times greater than the initial number of recognized craters. The formation systems of 18,996 newly detected craters larger than 8 km are esti- mated. Here, a new lunar crater database for the mid- and low-latitude regions of the Moon is derived and distributed to the planetary community together with the related data analysis. 1 College of Earth Sciences, Jilin University, 130061 Changchun, China. 2 Key Laboratory of Lunar and Deep Space Exploration, National Astronomical Observatories, Chinese Academy of Sciences, 100101 Beijing, China. 3 Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education, College of Computer Science and Technology, Jilin University, 130012 Changchun, China. 4 Department of Information Engineering and Computer ✉ Science, University of Trento, I-38122 Trento, Italy.
    [Show full text]
  • Glossary Glossary
    Glossary Glossary Albedo A measure of an object’s reflectivity. A pure white reflecting surface has an albedo of 1.0 (100%). A pitch-black, nonreflecting surface has an albedo of 0.0. The Moon is a fairly dark object with a combined albedo of 0.07 (reflecting 7% of the sunlight that falls upon it). The albedo range of the lunar maria is between 0.05 and 0.08. The brighter highlands have an albedo range from 0.09 to 0.15. Anorthosite Rocks rich in the mineral feldspar, making up much of the Moon’s bright highland regions. Aperture The diameter of a telescope’s objective lens or primary mirror. Apogee The point in the Moon’s orbit where it is furthest from the Earth. At apogee, the Moon can reach a maximum distance of 406,700 km from the Earth. Apollo The manned lunar program of the United States. Between July 1969 and December 1972, six Apollo missions landed on the Moon, allowing a total of 12 astronauts to explore its surface. Asteroid A minor planet. A large solid body of rock in orbit around the Sun. Banded crater A crater that displays dusky linear tracts on its inner walls and/or floor. 250 Basalt A dark, fine-grained volcanic rock, low in silicon, with a low viscosity. Basaltic material fills many of the Moon’s major basins, especially on the near side. Glossary Basin A very large circular impact structure (usually comprising multiple concentric rings) that usually displays some degree of flooding with lava. The largest and most conspicuous lava- flooded basins on the Moon are found on the near side, and most are filled to their outer edges with mare basalts.
    [Show full text]
  • Science Concept 5: Lunar Volcanism Provides a Window Into the Thermal and Compositional Evolution of the Moon
    Science Concept 5: Lunar Volcanism Provides a Window into the Thermal and Compositional Evolution of the Moon Science Concept 5: Lunar volcanism provides a window into the thermal and compositional evolution of the Moon Science Goals: a. Determine the origin and variability of lunar basalts. b. Determine the age of the youngest and oldest mare basalts. c. Determine the compositional range and extent of lunar pyroclastic deposits. d. Determine the flux of lunar volcanism and its evolution through space and time. INTRODUCTION Features of Lunar Volcanism The most prominent volcanic features on the lunar surface are the low albedo mare regions, which cover approximately 17% of the lunar surface (Fig. 5.1). Mare regions are generally considered to be made up of flood basalts, which are the product of highly voluminous basaltic volcanism. On the Moon, such flood basalts typically fill topographically-low impact basins up to 2000 m below the global mean elevation (Wilhelms, 1987). The mare regions are asymmetrically distributed on the lunar surface and cover about 33% of the nearside and only ~3% of the far-side (Wilhelms, 1987). Other volcanic surface features include pyroclastic deposits, domes, and rilles. These features occur on a much smaller scale than the mare flood basalts, but are no less important in understanding lunar volcanism and the internal evolution of the Moon. Table 5.1 outlines different types of volcanic features and their interpreted formational processes. TABLE 5.1 Lunar Volcanic Features Volcanic Feature Interpreted Process
    [Show full text]
  • The Moon After Apollo
    ICARUS 25, 495-537 (1975) The Moon after Apollo PAROUK EL-BAZ National Air and Space Museum, Smithsonian Institution, Washington, D.G- 20560 Received September 17, 1974 The Apollo missions have gradually increased our knowledge of the Moon's chemistry, age, and mode of formation of its surface features and materials. Apollo 11 and 12 landings proved that mare materials are volcanic rocks that were derived from deep-seated basaltic melts about 3.7 and 3.2 billion years ago, respec- tively. Later missions provided additional information on lunar mare basalts as well as the older, anorthositic, highland rocks. Data on the chemical make-up of returned samples were extended to larger areas of the Moon by orbiting geo- chemical experiments. These have also mapped inhomogeneities in lunar surface chemistry, including radioactive anomalies on both the near and far sides. Lunar samples and photographs indicate that the moon is a well-preserved museum of ancient impact scars. The crust of the Moon, which was formed about 4.6 billion years ago, was subjected to intensive metamorphism by large impacts. Although bombardment continues to the present day, the rate and size of impact- ing bodies were much greater in the first 0.7 billion years of the Moon's history. The last of the large, circular, multiringed basins occurred about 3.9 billion years ago. These basins, many of which show positive gravity anomalies (mascons), were flooded by volcanic basalts during a period of at least 600 million years. In addition to filling the circular basins, more so on the near side than on the far side, the basalts also covered lowlands and circum-basin troughs.
    [Show full text]
  • Lunar Sourcebook : a User's Guide to the Moon
    4 LUNAR SURFACE PROCESSES Friedrich Hörz, Richard Grieve, Grant Heiken, Paul Spudis, and Alan Binder The Moon’s surface is not affected by atmosphere, encounters with each other and with larger planets water, or life, the three major agents for altering throughout the lifetime of the solar system. These terrestrial surfaces. In addition, the lunar surface has orbital alterations are generally minor, but they not been shaped by recent geological activity, because ensure that, over geological periods, collisions with the lunar crust and mantle have been relatively cold other bodies will occur. and rigid throughout most of geological time. When such a collision happens, two outcomes are Convective internal mass transport, which dominates possible. If “target” and “projectile” are of comparable the dynamic Earth, is therefore largely absent on the size, collisional fragmentation and annihilation Moon, and so are the geological effects of such occurs, producing a large number of much smaller internal motions—volcanism, uplift, faulting, and fragments. If the target object is very large compared subduction—that both create and destroy surfaces on to the projectile, it behaves as an “infinite halfspace,” Earth. The great contrast between the ancient, stable and the result is an impact crater in the target body. Moon and the active, dynamic Earth is most clearly For collisions in the asteroid belt, many of the shown by the ages of their surfaces. Nearly 80% of the resulting collisional fragments or crater ejecta escape entire solid surface of Earth is <200 m.y. old. In the gravitational field of the impacted object; many of contrast, >99% of the lunar surface formed more than these fragments are then further perturbed into 3 b.y.
    [Show full text]
  • South Pole-Aitken Basin
    Feasibility Assessment of All Science Concepts within South Pole-Aitken Basin INTRODUCTION While most of the NRC 2007 Science Concepts can be investigated across the Moon, this chapter will focus on specifically how they can be addressed in the South Pole-Aitken Basin (SPA). SPA is potentially the largest impact crater in the Solar System (Stuart-Alexander, 1978), and covers most of the central southern farside (see Fig. 8.1). SPA is both topographically and compositionally distinct from the rest of the Moon, as well as potentially being the oldest identifiable structure on the surface (e.g., Jolliff et al., 2003). Determining the age of SPA was explicitly cited by the National Research Council (2007) as their second priority out of 35 goals. A major finding of our study is that nearly all science goals can be addressed within SPA. As the lunar south pole has many engineering advantages over other locations (e.g., areas with enhanced illumination and little temperature variation, hydrogen deposits), it has been proposed as a site for a future human lunar outpost. If this were to be the case, SPA would be the closest major geologic feature, and thus the primary target for long-distance traverses from the outpost. Clark et al. (2008) described four long traverses from the center of SPA going to Olivine Hill (Pieters et al., 2001), Oppenheimer Basin, Mare Ingenii, and Schrödinger Basin, with a stop at the South Pole. This chapter will identify other potential sites for future exploration across SPA, highlighting sites with both great scientific potential and proximity to the lunar South Pole.
    [Show full text]
  • The Geologic Context of Major Lunar Mare Pits. L
    3rd International Planetary Caves 2020 (LPI Contrib. No. 2197) 1048.pdf THE GEOLOGIC CONTEXT OF MAJOR LUNAR MARE PITS. L. Kerber1 L. M. Jozwiak2, J. Whitten3, R.V. Wagner4, B.W. Denevi2, , The Moon Diver Team. 1Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA, 91109 ([email protected]). 2Johns Hopkins Applied Physics Laboratory, Laurel, MD, 20723, 3Tulane University, New Orleans, LA, 70118, 4Arizona State Univeristy, Tempe, AZ, 85287. Introduction: In 2009, the Kaguya spacecraft dis- surface void [3]. The pit is located a few kilometers to covered several large pits in the lunar surface [1]. Later the west of the Rimae Burg graben, and could be relat- Lunar Reconaissance Orbiter Camera (LROC) images ed [7]. Compositionally, the pit is located in a deposit captured these pits in greater detail, revealing that of low- to very low-Ti and high Al2O3 lavas that extend some of them expose tens of meters of in-situ lava bed- from Lacus Mortis across the larger Mare Frigoris re- rock cross-sections in their walls [2,3]. Such exposures gion [8]. The Lacus Mortis region itself is a small, offer tantalizing natural drill-holes through the regolith semi-circular mare deposit to the south of Mare Frigor- and into the lunar maria. In particular, the pits provide is, and appears to be composed of a single basaltic unit the opportunity to examine maria deposits from the top [8]. The Lacus Mortis pit would provide access to 5-6 of the regolith, through the regolith/bedrock interface, layers of undersampled Al-rich lavas [8].
    [Show full text]
  • Ages of Large Lunar Impact Craters and Implications for Bombardment During the Moon’S Middle Age ⇑ Michelle R
    Icarus 225 (2013) 325–341 Contents lists available at SciVerse ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Ages of large lunar impact craters and implications for bombardment during the Moon’s middle age ⇑ Michelle R. Kirchoff , Clark R. Chapman, Simone Marchi, Kristen M. Curtis, Brian Enke, William F. Bottke Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302, United States article info abstract Article history: Standard lunar chronologies, based on combining lunar sample radiometric ages with impact crater den- Received 20 October 2012 sities of inferred associated units, have lately been questioned about the robustness of their interpreta- Revised 28 February 2013 tions of the temporal dependance of the lunar impact flux. In particular, there has been increasing focus Accepted 10 March 2013 on the ‘‘middle age’’ of lunar bombardment, from the end of the Late Heavy Bombardment (3.8 Ga) until Available online 1 April 2013 comparatively recent times (1 Ga). To gain a better understanding of impact flux in this time period, we determined and analyzed the cratering ages of selected terrains on the Moon. We required distinct ter- Keywords: rains with random locations and areas large enough to achieve good statistics for the small, superposed Moon, Surface crater size–frequency distributions to be compiled. Therefore, we selected 40 lunar craters with diameter Cratering Impact processes 90 km and determined the model ages of their floors by measuring the density of superposed craters using the Lunar Reconnaissance Orbiter Wide Angle Camera mosaic. Absolute model ages were computed using the Model Production Function of Marchi et al.
    [Show full text]
  • Lunar Impact Craters Identification and Age Estimation with Chang'e Data
    LETTE Lunar impact craters identification and age estimation with Chang'E data by deep and transfer learning Chen Yang1,2*, Haishi Zhao3, Lorenzo Bruzzone4, Jon Atli Benediktsson5, Yanchun Liang3, Bin Liu2, Xingguo Zeng2, Renchu Guan3*, Chunlai Li2* & Ziyuan Ouyang 2,6 Impact craters, as "lunar fossils", are the most dominant lunar recognized and age constrained craters are not adequate enough to surface features and occupy most of the Moon’s surface. Their reveal their evolutionary history and process. formation and evolution record the history of the Solar System. Lunar craters have the same genesis, i.e., impacts create craters that Sixty years of triumphs in the lunar exploration projects look similar in a near-circular depression structure. This is the main accumulated a large amount of lunar data. Currently, there are basis for the identification of craters. Different experiences, i.e., the 9137 existing recognized craters. However, only 1675 of them have formation and long-term alteration, lead to craters having a different been determined age, which is obviously not satisfactory to reveal complex morphology. Typical characteristics can demonstrate the evolution of the Moon. Identifying craters is a challenging task differences in orders of magnitude in size of the diameters, e.g. the due to their enormous difference in size, large variations in shape largest craters have a diameter of a few hundred kilometers, whereas and vast presence. Furthermore, estimating the age of craters is the smallest ones have a diameter of a few meters. They also show extraordinarily difficult due to their complex and different large variations in shape due to an overlap with other craters (see morphologies.
    [Show full text]
  • Geology of Shackleton Crater and the South Pole of the Moon Paul D
    GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L14201, doi:10.1029/2008GL034468, 2008 Geology of Shackleton Crater and the south pole of the Moon Paul D. Spudis,1 Ben Bussey,2 Jeffrey Plescia,2 Jean-Luc Josset,3 and Ste´phane Beauvivre4 Received 28 April 2008; revised 10 June 2008; accepted 16 June 2008; published 18 July 2008. [1] Using new SMART-1 AMIE images and Arecibo and details new results on the lighting conditions of the poles Goldstone high resolution radar images of the Moon, we [e.g., Bussey et al., 2008]. investigate the geological relations of the south pole, including the 20 km-diameter crater Shackleton. The south 2. Geological Setting of the South Pole pole is located inside the topographic rim of the South Pole- Aitken (SPA) basin, the largest and oldest impact crater on [3] The dominant feature that influences the geology and the Moon and Shackleton is located on the edge of an topography of the south polar region is the South Pole- interior basin massif. The crater Shackleton is found to be Aitken (SPA) basin, the largest and oldest impact feature on older than the mare surface of the Apollo 15 landing site the Moon [e.g., Wilhelms, 1987]. This feature is over 2600 (3.3 Ga), but younger than the Apollo 14 landing site km in diameter, averages 12 km depth, and is approximately (3.85 Ga). These results suggest that Shackleton may have centered at 56° S, 180° [Spudis et al., 1994]. The basin collected extra-lunar volatile elements for at least the last formed sometime after the crust had solidified and was rigid 2 billion years and is an attractive site for permanent human enough to support significant topographic expression; thus, presence on the Moon.
    [Show full text]
  • Understanding the Lunar Surface and Space-Moon Interactions Paul Lucey1, Randy L
    Reviews in Mineralogy & Geochemistry Vol. 60, pp. 83-219, 2006 2 Copyright © Mineralogical Society of America Understanding the Lunar Surface and Space-Moon Interactions Paul Lucey1, Randy L. Korotev2, Jeffrey J. Gillis1, Larry A. Taylor3, David Lawrence4, Bruce A. Campbell5, Rick Elphic4, Bill Feldman4, Lon L. Hood6, Donald Hunten7, Michael Mendillo8, Sarah Noble9, James J. Papike10, Robert C. Reedy10, Stefanie Lawson11, Tom Prettyman4, Olivier Gasnault12, Sylvestre Maurice12 1University of Hawaii at Manoa, Honolulu, Hawaii, U.S.A. 2Washington University, St. Louis, Missouri, U.S.A. 3University of Tennessee, Knoxville, Tennessee, U.S.A. 4Los Alamos National Laboratory, Los Alamos, New Mexico, U.S.A. 5Smithsonian Institution, Washington D.C., U.S.A. 6Lunar and Planetary Laboratory, Univ. of Arizona, Tucson, Arizona, U.S.A. 7University of Arizona, Tucson, Arizona, U.S.A. 8Boston University, Cambridge, Massachusetts, U.S.A. 9Brown University, Providence, Rhode Island, U.S.A. 10University of New Mexico, Albuquerque, New Mexico, U.S.A. 11 Northrop Grumman, Van Nuys, California, U.S.A. 12Centre d’Etude Spatiale des Rayonnements, Toulouse, France Corresponding authors e-mail: Paul Lucey <[email protected]> Randy Korotev <[email protected]> 1. INTRODUCTION The surface of the Moon is a critical boundary that shapes our understanding of the Moon as a whole. All geologic mapping and remote sensing techniques utilize only the outermost portion of the Moon. Before leaving the Moon for study in our laboratories, all lunar samples that have been studied existed at or very near the surface. With the exception of the deeply probing geophysical techniques, our understanding of the interior of the Moon is derived from surficial, but not superficial, information, coupled with geologic reasoning.
    [Show full text]
  • Examining Spectral Variations in Localized Lunar Dark Mantle Deposits Erica R
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln USGS Staff -- ubP lished Research US Geological Survey 2015 Examining spectral variations in localized lunar dark mantle deposits Erica R. Jawin European Space Research and Technology Center, Noordwijk, Netherlands, [email protected] Sebastien Besse European Space Research and Technology Center, Noordwijk, Netherlands Lisa R. Gaddis USGS Astrogeology Science Center, Flagstaff, Arizona Jessica M. Sunshine University of Maryland James W. Head Brown University See next page for additional authors Follow this and additional works at: http://digitalcommons.unl.edu/usgsstaffpub Jawin, Erica R.; Besse, Sebastien; Gaddis, Lisa R.; Sunshine, Jessica M.; Head, James W.; and Mazrouei, Sara, "Examining spectral variations in localized lunar dark mantle deposits" (2015). USGS Staff -- Published Research. 861. http://digitalcommons.unl.edu/usgsstaffpub/861 This Article is brought to you for free and open access by the US Geological Survey at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USGS Staff -- ubP lished Research by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Erica R. Jawin, Sebastien Besse, Lisa R. Gaddis, Jessica M. Sunshine, James W. Head, and Sara Mazrouei This article is available at DigitalCommons@University of Nebraska - Lincoln: http://digitalcommons.unl.edu/usgsstaffpub/861 PUBLICATIONS Journal of Geophysical Research: Planets RESEARCH ARTICLE Examining spectral variations
    [Show full text]